sundtek-mediatv: fixed (some) errors

And decision should be made: keeping this addon alive as part of openelec or not. In second case I will maintain it and build it myself totally unofficially.
CHECK_BOOT should be removed after you re-enable this setting block (CHECK_BOOT would still be set for old users and the update logic  in sundtek*.start would still try to autoupdate?). this is a call for trouble. you have ZERO guarantee that network is ready at the time this starts..